PROJECT SUMMARY/ABSTRACT Hemophilia is caused by an inherited deficiency of clotting factor proteins, leading to both spontaneous and trauma-induced bleeding. Bleeding into joints and muscles causes acute pain, and over time repeated bleeds into joints results in arthropathy, physical disability, and chronic pain in a large proportion of adults with hemophilia. Effective management of pain in persons with hemophilia (PWH) is severely limited due to lack of valid and reliable methods for measuring pain and incorporating this information into hemophilia clinical care practices. This study addresses this critical barrier to progress toward the long-term goal of reducing the impact of pain on the lives of PWH. The overall objectives of this study are to determine whether Patient- Reported Outcomes Measurement Information System (PROMIS) measures of pain intensity, interference, and behavior are valid and reliable for use in PWH and to identify factors that affect implementation of pain measurement practices within hemophilia treatment centers (HTCs). The immediate goals of the candidate for this K23 award, Dr. Tyler Buckner, are to obtain new knowledge, skills, and experience that will allow him to test the validity, reliability, and responsiveness of existing patient-reported outcome (PRO) measures in special populations, design longitudinal studies and conduct analyses of measures repeated over time, and study the implementation of incorporating PRO assessments into clinical practice. Achieving these goals will support his long term career goal of becoming a leader in the effort to improve the way that pain is assessed and managed in the hemophilia clinic. Dr. Buckner will accomplish his research and training aims with the support of his mentors, Dr. Marilyn Manco-Johnson (hemophilia clinical research), Dr. Bryce Reeve (psychometrics), Dr. Diane Fairclough (longitudinal analysis), and Dr. Jodi Holtrop (implementation science). Dr. Buckner's plan for career development is enhanced by the outstanding research environment at the University of Colorado, which provides junior faculty members with numerous didactic and training opportunities designed specifically to facilitate the transition to research career independence. The facilities and clinical and research staff of the University of Colorado HTC provide an outstanding research infrastructure that will also support Dr. Buckner's career development and research activities. Dr. Buckner's research aims to assess the following: 1) reliability and validity of PROMIS measures of pain in PWH, 2) responsiveness and ecological validity of these measures in PWH, and 3) feasibility and acceptability of implementing in-clinic and at-home pain assessments in this population. These aims will be accomplished using computerized adaptive tests to conduct both cross- sectional and longitudinal studies of the PROMIS pain measures in men with hemophilia. By completing his research and training aims, Dr. Buckner will advance the science of pain assessment in hemophilia and make a significant contribution to improving the clinical care of PWH, while also obtaining experience and training necessary to begin his career as an independent investigator and leader in hemophilia outcomes research.